Systems and methods for providing wireless asymmetric network architectures of wireless devices with power management features

ABSTRACT

Systems and methods for implementing power management features while providing a wireless asymmetric network are disclosed herein. In one embodiment, a system includes a hub having a wireless control device that is configured to control communications and power consumption in the wireless asymmetric network architecture and sensor nodes each having at least one sensor and a wireless device with a transmitter and a receiver to enable bi-directional communications with the wireless control device of the hub. The wireless control device is configured to determine a scheduled timing of operating each sensor node during a first time period that is close in time with respect to a transmit window of the transmitter and during a second time period that is close in time with respect to a receive window of the receiver for each wireless device to reduce power consumption of the wireless devices of the sensor nodes.

RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.14/607,048, filed on Jan. 27, 2015, the entire contents of which arehereby incorporated by reference.

This application is related to application Ser. No. ______, filed Jan.27, 2015, entitled: SYSTEMS AND METHODS FOR PROVIDING WIRELESS SENSORNETWORKS WITH AN ASYMMETRIC NETWORK ARCHITECTURE; application Ser. No.______, filed Jan. 27, 2015, entitled: SYSTEMS AND METHODS FOR PROVIDINGWIRELESS ASYMMETRIC NETWORK ARCHITECTURES OF WIRELESS DEVICES WITHANTI-COLLISION FEATURES; and application Ser. No. ______, filed Jan. 27,2015, entitled: SYSTEMS AND METHODS FOR DETERMINING LOCATIONS OFWIRELESS SENSOR NODES IN AN ASYMMETRIC NETWORK ARCHITECTURE.

FIELD

Embodiments of the invention pertain to systems and methods forproviding wireless asymmetric network architectures of wireless deviceswith power management features.

BACKGROUND

In the consumer electronics and computer industries, wireless sensornetworks have been studied for many years. In archetypal wireless sensornetworks, one or more sensors are implement in conjunction with a radioto enable wireless collection of data from one or more sensor nodesdeployed within a network. Each sensor node may include one or moresensors, and will include a radio and a power source for powering theoperation of the sensor node.

Wireless conventional sensor networks suffer from certain deficienciesthat affect their operation, efficiency, cost, and ability to beimplemented in indoor environments.

SUMMARY

For one embodiment of the present invention, a system with powermanagement features for providing a wireless asymmetric network isdisclosed herein. The system includes a hub having a wireless controldevice that is configured to control communications and powerconsumption in the wireless asymmetric network architecture. The systemalso includes a plurality of nodes each having a wireless device with atransmitter and a receiver to enable bi-directional communications withthe wireless control device of the hub in the wireless asymmetricnetwork architecture. The wireless control device can be configured todetermine a scheduled timing of causing the transmitter to be operableto transmit and causing the receiver to be operable to receive for eachwireless device to reduce power consumption of the wireless devices ofthe plurality of nodes.

In another embodiment, a system for providing a wireless asymmetricnetwork architecture with anti-collision features includes a first hubhaving a wireless control device that is configured to controlcommunications in the wireless asymmetric network architecture and afirst plurality of nodes each having a wireless device with atransmitter and a receiver to enable bi-directional communications withthe wireless control device of the first hub in the wireless asymmetricnetwork architecture. The wireless control device of the first hub isconfigured to detect a communication from a first node of the firstplurality of nodes, determine whether at least a portion of thecommunication is unintelligible to circuitry of the first hub orcircuitry coupled to the first hub, and determine whether a collision ofcommunications transmitting at approximately the same time from thefirst node and a second node has likely occurred when the at leastportion of the communication is unintelligible.

The system may also include a second hub having a wireless controldevice that is configured to control communications in the wirelessasymmetric network architecture and a second plurality of nodes eachhaving a wireless device with a transmitter and a receiver to enablebi-directional communications with the wireless control device of thesecond hub in the wireless asymmetric network architecture. The wirelesscontrol device of the second hub is configured to determine a transmitwindow for a transmitter and a receive window for a receiver of eachwireless device of the second plurality of nodes and provideanti-collision features to avoid collisions of the communicationsreceived from the wireless devices of the second plurality of nodes.

In another embodiment, a system for providing a wireless asymmetricnetwork architecture includes power management features. The systemincludes a hub having a wireless control device that is configured tocontrol communications and power consumption in the wireless asymmetricnetwork architecture and a plurality of sensor nodes each having atleast one sensor and a wireless device with a transmitter and a receiverto enable bi-directional communications with the wireless control deviceof the hub in the wireless asymmetric network architecture. The wirelesscontrol device is configured to determine a scheduled timing ofoperating each sensor node during a first time period that is close intime with respect to a transmit window of the transmitter and during asecond time period that is close in time with respect to a receivewindow of the receiver for each wireless device to reduce powerconsumption of the wireless devices of the plurality of sensor nodes.

In one example, each sensor node operates at a first power consumptionlevel for the first and second time periods. Each sensor node mayoperate at a second power consumption level when outside of the firstand second time periods. For this example, the first power consumptionlevel has more power consumption than the second power consumptionlevel.

In another embodiment, an apparatus (e.g., hub) for providing a wirelessasymmetric network architecture includes a memory for storinginstructions, one or more processing units to execute instructions toestablish and control communications in a wireless asymmetric networkarchitecture, and radio frequency (RF) circuitry including multipleantennas to transmit and receive communications in the wirelessasymmetric network architecture. The RF circuitry may include multipleantennas to transmit communications to a plurality of sensor nodes eachhaving a wireless device with a transmitter and a receiver to enablebi-directional communications with the RF circuitry of the apparatus inthe wireless asymmetric network architecture. The one or more processingunits are configured to execute instructions to determine locationinformation for the plurality of sensor nodes based on receivingcommunications from each sensor node.

Other features and advantages of embodiments of the present inventionwill be apparent from the accompanying drawings and from the detaileddescription that follows below.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention are illustrated by way of exampleand not limitation in the figures of the accompanying drawings, in whichlike references indicate similar elements, and in which:

FIG. 1 shows an archetypal mesh-type wireless sensor network.

FIG. 2 shows an archetypal tree-type wireless sensor network.

FIG. 3 shows the conceptual basis for frequency division multiplexing.

FIG. 4 shows the conceptual basis for time division multiplexing.

FIG. 5 shows the conceptual basis for code division multiplexing

FIG. 6 is an asymmetric tree network architecture in accordance with oneembodiment.

FIG. 7 shows a system with an asymmetric tree and mesh networkarchitecture having multiple hubs in accordance with one embodiment.

FIG. 8A shows an exemplary embodiment of a hub implemented as an overlay800 for an electrical power outlet in accordance with one embodiment.

FIG. 8B shows an exemplary embodiment of an exploded view of a blockdiagram of a hub 820 implemented as an overlay for an electrical poweroutlet in accordance with one embodiment.

FIG. 9A shows an exemplary embodiment of a hub implemented as a card fordeployment in a computer system, appliance, or communication hub inaccordance with one embodiment.

FIG. 9B shows an exemplary embodiment of a block diagram of a hub 964implemented as a card for deployment in a computer system, appliance, orcommunication hub in accordance with one embodiment.

FIG. 9C shows an exemplary embodiment of a hub implemented within anappliance (e.g., smart washing machine, smart refrigerator, smartthermostat, other smart appliances, etc.) in accordance with oneembodiment.

FIG. 9D shows an exemplary embodiment of an exploded view of a blockdiagram of a hub 984 implemented within an appliance (e.g., smartwashing machine, smart refrigerator, smart thermostat, other smartappliances, etc.) in accordance with one embodiment.

FIG. 10 illustrates a flow chart for a method of providingcommunications for a wireless asymmetric network architecture inaccordance with one embodiment.

FIG. 11 illustrates a time sequence for shifting transmit and receivecommunications to avoid collisions in a wireless asymmetric networkarchitecture in accordance with one embodiment.

FIG. 12 illustrates a method of arbitration and collision avoidance forcommunications in a wireless asymmetric network architecture inaccordance with one embodiment.

FIG. 13 illustrates a flow chart for a method of providingimplementation of sensor localization for a wireless asymmetric networkarchitecture in accordance with one embodiment.

FIG. 14 illustrates use of multiple antennas on an apparatus (e.g., hub)and a multipath environment to enable sensor localization in accordancewith one embodiment.

FIG. 15 illustrates use of multiple hubs each having a single antenna toachieve localization in accordance with one embodiment.

FIG. 16 illustrates a flow chart for a method of providing a wirelessasymmetric network architecture with a hub having power managementfeatures in accordance with one embodiment.

FIG. 17 illustrates a block diagram of a sensor node in accordance withone embodiment.

FIG. 18 illustrates a block diagram of a system or appliance 1800 havinga hub in accordance with one embodiment.

FIG. 19 illustrates a block diagram of a vibrational energy harvestingsystem for providing a supplemental energy source to a sensor node inaccordance with one embodiment.

FIG. 20 illustrates a block diagram of a vibrational energy harvestingsystem for charging a rechargeable battery of a sensor node inaccordance with another embodiment.

FIG. 21 illustrates a block diagram of a photovoltaic energy harvestingsystem for charging a rechargeable battery of a sensor node inaccordance with one embodiment.

DETAILED DESCRIPTION

Systems and methods for implementing power management features whileproviding a wireless asymmetric network are disclosed herein. In oneembodiment, a system includes a hub having a wireless control devicethat is configured to control communications and power consumption inthe wireless asymmetric network architecture and sensor nodes eachhaving at least one sensor and a wireless device with a transmitter anda receiver to enable bi-directional communications with the wirelesscontrol device of the hub. The wireless control device is configured todetermine a scheduled timing of operating each sensor node during afirst time period that is close in time with respect to a transmitwindow of the transmitter and during a second time period that is closein time with respect to a receive window of the receiver for eachwireless device to reduce power consumption of the wireless devices ofthe sensor nodes.

A wireless sensor network is described for use in an indoor environmentincluding homes, apartments, office and commercial buildings, and nearbyexterior locations such as parking lots, walkways, and gardens. Thewireless sensor network may also be used in any type of building,structure, enclosure, vehicle, boat, etc. having a power source. Thesensor system provides good battery life for sensor nodes whilemaintaining long communication distances. Additional aspects ofembodiments of the invention provide ability to achieve sensorlocalization, collision avoidance, mitigation of self-discharge, andimplementation of energy harvesting.

Embodiments of the invention provide advantages in power management suchas providing a wireless sensor network for use in indoor and nearbyexterior environments with enhanced battery life. The asymmetry ofavailable power in indoor and nearby exterior environments is exploitedto enhance battery life and communication range in wireless sensornetworks deployed in such environments.

Embodiments of the invention exploit the use of low-duty cyclenetworking to reduce transmission-related energy consumption in awireless sensor network for use in indoor and nearby exteriorenvironments, thus providing improved battery life.

Anti-collision features provide a means of avoiding communicationcollisions in a wireless sensor network for use in indoor and nearbyexterior environments without expending excessive energy oncommunications associated with collision avoidance.

Sensor localization features provide a wireless sensor network offeringprecise localization of individual sensor nodes in indoor and nearbyexterior environments.

Energy scavenging features provide a wireless sensor network for use inindoor and nearby exterior environments with battery-optimized energyscavenging.

Embodiments of the invention provide a battery-operated sensor nodearchitecture offering robust communication and long battery life withinindoor and similar environments, along with ability to preciselydetermine location of the sensor node within the physical environment ofthe wireless sensor network.

Conventional wireless sensor networks make use of a variety ofcommunication and power supply schemes. In one communication scheme, amesh network is used, where sensor nodes within the wireless sensornetworks act as routers. In this scheme, each node can send dataoriginating within itself, can receive data from other nodes or devices,and can route data received from other nodes or devices on to stillother nodes or devices. In this last manner, the sensor node behaves asa repeater, in that it passes on data not originating within itself.FIG. 1 shows a schematic representation of a wireless sensor networkimplemented as a mesh network. Each of the nodes 1-10 can send dataoriginating within itself, can receive data from other nodes or devices,and can route data received from other nodes or devices to still othernodes or devices

In another communication scheme, the network may be implemented in atree structure, such that the network is organized into nodes forming atree structure, with a root linked to branches, branches linked to otherbranches and to terminals, and finally terminals on the lowest level ofhierarchy. Such a network structure is shown in FIG. 2. In this system,terminal nodes 7-25 only communicate to a respective branch node (e.g.,2-6) above a terminal node, and do not communicate directly to eachother. For example, terminal nodes 11-14 only communicate with branchnode 3 and do not communicate directly to each other. Similarly,branches nodes communicate to terminal nodes below them, and to branchesnodes (e.g., branch node 1) above them, but not directly communicate tobranches nodes on the same level of hierarchy. For example, branch node4 communicates with branch node 1 but does not directly communicate withbranch nodes 2, 3, 5, and 6. In this manner, a tree network isimplemented.

Since multiple wireless sensor networks in a typical wireless sensornetwork may be located within the same physical environment, there is arisk of collisions during wireless communication. A collision is definedas an event when two or more nodes attempt to communicate at the sametime, resulting in at least a portion of the communication beingunintelligible (e.g., garbled, distorted) to a processing circuit.Various strategies to avoid or mitigate collisions have been disclosed.In one means of avoiding collisions, frequency division multiplexing maybe used as illustrated in the exemplary diagram 300 of FIG. 3. In thissystem, individual nodes may be assigned specific dedicated frequenciesover which to communicate. By allocating different frequencies such twonodes at risk of collision do not communicate at the same frequency,thus collisions can be avoided. In this exemplary diagram 300, theavailable frequency spectrum is divided into frames (e.g., frames 1-4)on a vertical frequency axis 310 and the frames are in turn divided intoslots (e.g., slots 1-4). In the exemplar diagram, there are four framesand four slots available at any point in time on a horizontal time axis320. By allocating slots between individual users (e.g., users 1-4), 4separate users can transmit at the same time without collision.

In another means of avoiding collisions, time division multiplexing maybe used as illustrating in an exemplary diagram 400 of FIG. 4. In thissystem, individual nodes may be assigned specific time slices duringwhich the nodes may communicate. By allocating time slices such that twonodes at risk of communication do not communicate during the same timeslice, collisions can be avoided. The time slices (e.g., 1-4) of frames1-4 as shown on a time axis 420 may be pre-defined, or may beestablished using a beacon or broadcast synchronization signal. In thisdiagram 400, multiple users (for example, multiple sensor nodes) mayshare the same frequency band of frequency axis 410 by usingindividually separate time slots. Since no two users transmit during thesame time slot, collisions can be avoided.

In another means of avoiding collisions, code division multiplexing maybe used. In this system, the available frequency spectrum for radiotransmission is chosen to be wide enough that multiple nodes cancommunicate at the same carrier frequency using different spreadingcodes. This in turn allows for avoidance of collisions. This system iscommonly used in cellular communication, for example, as shown in FIG.5. In this system 500, the same general frequency spectrum is used bymultiple users. However, individual users use different and separablespreading codes, such that they can be deconvoluted from each otherdespite sharing the same frequency and time space. For example, a userof a device 502 sends a communication 512 to a user of a device 503. Thecommunication 512 is encoded and decoded with the purple code 510. Atthe same time, a user of a device 504 sends a communication 530 to auser of a device 505. The communication 530 is encoded and decoded withthe green code 530.

In yet another means of avoiding collisions, spatial separation ofsensor communications may be used, such that collisions are avoided bypreventing colliding communications in the same physical space. This maybe achieved by physically placing the sensors in different locations orby controlling the shape and extent of electromagnetic radiationassociated with a particular communication event.

Electrical power for the operation of individual sensor nodes may beobtained in numerous ways. Power may be provided by connectingindividual nodes to a battery. Power may also be provided by connectingindividual nodes to electrical means, for example, by using a plug.Power may also be provided via energy harvesting, where energy isharvested by the node from available external energy sources. Theseenergy sources could include vibration, solar power, electromagneticradiation, heat, and other similar sources of harvestable energy. Theharvestable energy may be incidental or may be deliberately madeavailable to the node. The former may be the case, for example, in awireless sensor network operating in a bright environment, such thatsolar power is incidentally available, while the latter may be the casein an environment where inductive power coupling is used to specificallytransfer power to the sensor node from an external transmitter.

In many wireless sensor network applications, it is desirable todetermine the location of the individual sensor nodes. In conventionalwireless sensor networks, this has been achieved in various ways. In afirst example, distance between sensor nodes is determined by usingdistance-dependent communication effects to estimate distances betweentwo sensor nodes communicating with each other. In a mesh network, byexploiting the various communication paths in the mesh, positioning ofeach node can be estimated based on the various estimated distances. Inanother example, location information is transmitted by each sensornode, thus specifying the location of the various nodes within thesensor network. The location may be determined using existinglocalization services such as the global positioning service (GPS).

The conventional approaches discussed herein suffer from certaindeficiencies that affect their operation, efficiency, cost, and/orability to be implemented in and around indoor environments such aswould exist in homes, apartments, office and commercial buildings, andnearby exterior locations such as parking lots, walkways, and gardens.In particular, in such environments, there is a substantial asymmetry inavailable power, such that some locations will have access to plenty ofpower while others will be relatively power-starved. For example,locations close to electrical outlets will have access to power from theoutlet, and locations in bright sunlight will have access to solarpower, while locations away from the walls and in dark locations mightbe relatively power starved. In these applications, the previouslydescribed wireless sensor networks suffer from shortcomings that limittheir operation, since these approaches do not exploit this asymmetryand are rather limited in their use of communication protocols, poweravailability, and overall operation. Furthermore, in indoorenvironments, localization strategies are altered. For example, GPStypically does not work well indoors due to poor satellite signalpenetration. Similarly, the presence of multiple potential reflectingsurfaces can complicate or prevent localization using iterativemulti-point distance calculations.

In a typical wireless communication device, instantaneous power totransmit is usually significantly larger than instantaneous powerrequired to receive. The power required in transmission is typicallydirectly related to the desired range of communication, since the signalstrength received at the target location must be sufficiently large asto enable discernment over the noise at that location. Range can thus beincreased by increasing signal strength of the transmitted signal; thisresults in an increase in the power consumed during transmission. On theother hand, the power required to receive depends on the fraction oftime during which the receive radio is operational for receivingtransmitted signals (e.g., communications).

Mesh networks can reduce the power required during transmission by usingmultiple shorter hops rather than one long hop between nodes. On theother hand, in mesh networks, since the receive radio must be on most orall of the time to enable reception and/or relaying of signals fromneighboring mesh nodes, the energy required to receive may besignificantly larger than receive energy required to receive in networkarchitectures in which the receive radio is only on sporadically.Therefore, systems in which only small amounts of data need to betransmitted, mesh networks can suffer from drawbacks with respect toenergy consumption and thus with respect to battery life. Given thesmall amount of data required to be transmitted, such systems can beoperated at low transmit duty cycles, such that the total transmitenergy can be low despite a high transmit power requirement. In suchsystems, receive power becomes a greater concern therefore. As aconsequence, mesh networks can have unfavorable power consumptionrequirements since the receive radios must be on for a substantialfraction of time to support the requisite mesh communications.

Even in mesh networks that eliminate repeater functionality in batteryoperated nodes, such drawbacks can still exist since thebattery-operated nodes must still expend significant power to maintaintransmit and receive compatibility with the mesh network architecture ofthe overall network.

Conventional tree networks suffer from drawbacks as well. Inconventional tree networks working in indoor requirements, the powerrequired to transmit can be high. In particular, since tree networkscannot exploit short-hop communications without having a high-density ofhubs, tree networks can have significant node energy consumptionassociated with transmission due to the need to provide higher transmitpowers to achieve robust communication over the long distances betweennodes and hubs.

Conventional wireless sensor networks have drawbacks when used insystems requiring only small amounts of data transmission, such as mightexist for collections of simple sensing functions. In such systems, thelow amount of data required to be transmitted may result in poorutilization of the network capacity, resulting in a significant waste ofenergy in a network that does not duty cycle such that battery operatednodes are only in an operational mode for a small fraction of the time.

Conventional battery operated wireless sensor nodes can suffer from poorbattery life since they can lose available battery energy due toself-discharge. This is a particular concern in systems running underlow duty cycles of operation, since battery capacity is continuouslylost due to self-discharge even when the node itself is in a low-energysleep state.

Conventional wireless sensor networks have disadvantages in that theymay be unable to localize individual sensor nodes or may require the useof multiple reception points to enable triangulation of sensor nodelocations or may require access to external localization systems orbeacons such as GPS. Particularly in indoor environments, withsignificant risk of multi-path signal propagation, narrow-band sensorsystems can suffer from poor or non-functional sensor localizationability due to signal degradation and temporal dispersion associatedwith multi-path events. Similarly, in indoor environments, availabilityof external localization systems or beacons such as GPS may be minimalor non-existing, preventing sensor localization. Even in networksutilizing ultra-wide-band communication, localization may be limited bythe need to use multiple reception points to achieve triangulation ofsensor position. This can result in increased overall network complexityand cost.

Conventional wireless sensor networks have additional disadvantages inthat these wireless sensor networks may expend significant energy oncollision avoidance during communication. Some conventional wirelesssensor networks require implementation of frequency divisionmultiplexing, which requires use of precisely tuned circuits. Theoperation of these circuits may expend significant energy due to powerconsumption associated with the tuned RF stages. On the other hand,conventional wireless sensor network systems implementing time divisionmultiplexing may consume significant power due to the power consumptionof the transmit and receive radios required to manage the time slicesynchronization. In conventional systems implementing code divisionmultiplexing, significant power may be expended in the circuitryimplementing coding functions, due to the complexity of coding anddecoding.

Wireless sensor networks including battery operated sensor nodestypically suffer from trade-offs between sensor communication range andbattery life. Longer range of sensor network operation may be achievedby using higher power radio transmissions from the sensor nodes or byimplementing a mesh network where individual nodes act as repeaters orrouters to provide multi-hop communication over the physical range ofthe wireless sensor network. In the former example, sensor node powerconsumption is increased due to the higher expenditure on transmitpower. In the latter example, both transmit and receive power may beincreased. Transmit power is increased due to the increased networktraffic involved in implementing the mesh network, while receive poweris increased due to the need to have the receive radio on for largeperiods of time to monitor for incoming network traffic.

As a consequence of the energy costs associated with these communicationactivities, battery life on battery-operated sensor nodes is oftenlimited. In indoor environments, it is to be noted that power foroperation of sensor nodes and the wireless sensor network is plentifulin specific locations. In one embodiment, indoor environments includeindoor and nearby exterior locations as would exist, for example, inhomes, apartments, office and commercial buildings, and nearby exteriorlocations such as, for example, parking lots, walkways, and gardens. Inone example, power is available at the specific locations of poweroutlets within a room environment or along exterior walls. Power is alsoavailable in areas of extensive sun exposure due to the ability togenerate adequate solar power. Other examples of locally available powerwould be apparent to one of ordinary skill in the art. As a result,indoor environments offer a significant asymmetry in power availability,such that some nodes within a wireless sensor network deployed in suchan environment would have plentiful access to external power sources,with other nodes in such an environment may be limited to the energystored in an attached power source (e.g., battery).

In one embodiment, an asymmetry in power availability may be exploitedto provide long range of communication in a wireless asymmetric networkarchitecture while maintaining long battery life for nodes that arepowered by a battery source. In an exemplary embodiment, a communicationrange of 20 meters between communicating nodes may be achieved whileproviding a long battery life (e.g., approximately 10 years, at leastten years) in battery operated nodes. This may be achieved byimplementing an energy aware networking protocol in accordance withembodiments of this invention. Specifically, a tree-like networkarchitecture may be used where long-life battery operated nodes are usedon the terminal ends of the tree.

FIG. 6 shows a system with an asymmetric tree network architecture inaccordance with one embodiment. The system 600 includes one hub 610having a wireless control device 612 and three nodes 620, 630, and 640that each include a wireless device 621, 631, and 641, respectively.Each wireless device includes RF circuitry (e.g., a transceiver withtransmitter functionality and receiver functionality, a transmitter anda receiver) to enable bi-directional communications includingcommunications 622, 624, 632, 634, 642, and 644 with the wirelesscontrol device of the hub 610 in the wireless asymmetric networkarchitecture. For example, a sensor node 630 transmits a communication632 (e.g., transmit communication of sensor node 630) and receives acommunication 634 (e.g., receive communication of sensor node 630) fromhub 610. From the perspective of the hub 610, the communication 632 is areceive communication and the communication 634 is a transmitcommunication for the hub. The wireless control device is configured todetermine a scheduled timing of causing the transmitter to be operableto transmit and causing the receiver to be operable to receive for eachwireless device to reduce power consumption of the wireless devices ofthe nodes 620, 630, and 640.

In one embodiment, the hub 610 is powered by a mains electrical source(e.g., alternating-current (AC) electric power supply) and the nodes areeach powered by a battery source or another energy source (not mainselectrical source) to form the wireless asymmetric network. Thescheduled timing of powering the transmitter and powering the receiverfor each wireless device of the nodes is determined based on a timing ofcommunications between the hub and each wireless device of the nodes.

In one example, the transmitter for each wireless device of the nodes isoperable for transmitting less than 5 percent of a time period and thereceiver for each wireless device of the first plurality of nodes isoperable for receiving less than 5 percent of the time period. Inanother example, the transmitter for each wireless device of the nodesis operable for transmitting less than 1 percent of a time period andthe receiver for each wireless device of the nodes is operable forreceiving less than 1 percent of the time period. The nodes are in anon-communicative state when the transmitter and the receiver of thewireless devices are not operable for transmitting and receiving,respectively.

The sensor nodes include one or more sensors including image sensors,moisture sensors, temperature sensors, humidity sensors, air qualitysensors, light sensors, motion sensors, and audio sensors, etc. fordifferent applications including home and office integrity and security.For example, the motion sensors may sense motion in order to determinewhether a door or window has been unlocked and image sensors obtainimages to determine whether an intruder has forced entry into a home orbuilding. In this case, an alarm or warning signal can be sent to adevice (e.g., source device, client device, mobile device, tabletdevice, computing device, etc.) of a home owner or owner of thebuilding.

In another example, moisture sensors may determine whether a home orbuilding has a potential leak or moisture issue. In some of theseembodiments, it may sometimes be desirable for a sensor to communicatewithout waiting for its allotted time slot or transmit window. Forexample, such a situation may occur when an alarm sensor detects anintruder. In this instance, the sensor may transmit immediately, and thehub will receive the information since the hub has plenty of power andis always operable to receive. On the other hand, such a network willstill benefit from the power reduction achieved by the hub-controlledtransmit and receive windows during normal operation.

In certain embodiments, multiple hubs may communicate with each other,multiple nodes may communicate with multiple hubs, and hubs and nodesmay be organized in more tiers so as to implement a multi-level treenetwork.

FIG. 7 shows a system with an asymmetric tree and mesh networkarchitecture having multiple hubs in accordance with one embodiment. Thesystem 700 includes a central hub 710 having a wireless control device712, hub 720 having a wireless control device 721, hub 782 having awireless control device 783, and additional hubs including hub n havinga wireless control device n. Additional hubs which are not shown cancommunicate with the central hub 710, other hubs, or can be anadditional central hub. Each hub communicates bi-directionally withother hubs and one or more sensor nodes. The hubs are also designed tocommunicate bi-directionally with other devices including device 780(e.g., client device, mobile device, tablet device, computing device,smart appliance, smart TV, etc.).

The sensor nodes 730, 740, 750, 760, 770, 788, 792, n, and n+1 (orterminal nodes) each include a wireless device 731, 741, 751, 761, 771,789, 793, n, and n+1, respectively. A sensor node is a terminal node ifit only has upstream communications with a higher level hub or node andno downstream communications with another hub or node. Each wirelessdevice includes RF circuitry with a transmitter and a receiver (ortransceiver) to enable bi-directional communications with hubs or othersensor nodes.

In one embodiment, the central hub 710 communicates with hubs 720, 782,hub n, device 780, and nodes 760 and 770. These communications includecommunications 732, 734, 742, 744, 752, 754, 774, 772, 764, 762, 781,784, 786, 714, and 712 in the wireless asymmetric network architecture.The central hub having the wireless control device 711 is configured tosend communications to other hubs and to receive communications from theother hubs for controlling and monitoring the wireless asymmetricnetwork architecture.

The hub 720 communicates with central hub 710 and also sensors nodes730, 740, and 750. The communications with these sensor nodes includecommunications 732, 734, 742, 744, 752, and 754. For example, from theperspective of the hub 720, the communication 732 is received by the huband the communication 734 is transmitted to the sensor node. From theperspective of the sensor node 730, the communication 732 is transmittedto the hub 720 and the communication 734 is received from the hub.

The wireless control device 721 is configured to determine a scheduledtiming of causing the transmitter to be operable to transmit and causingthe receiver to be operable to receive for each wireless device 731,741, 750 to reduce power consumption of the wireless devices of thenodes 730, 740, and 750.

The wireless control device 711 of the central hub 710 is configured todetermine a scheduled timing of causing the transmitter to be operableto transmit and causing the receiver to be operable to receive for eachwireless device to reduce power consumption of the wireless devices ofthe nodes. For example, the wireless control device 711 of the centralhub 710 is configured to determine a scheduled timing of causing thetransmitter to be operable to transmit and causing the receiver to beoperable to receive for each wireless device 761 and 771 to reduce powerconsumption of the wireless devices of the nodes 760 and 770.

In another example, the wireless control device 711 of the central hub710 is also configured to determine a scheduled timing of causing thetransmitter to be operable to transmit and causing the receiver to beoperable to receive for each wireless control device of the hubs 720,782, and n to reduce power consumption of these hubs particularly ifthese hubs are not powered by a mains electrical source.

In one embodiment, the central hub 710, hub 720, hub 782, and hub n arepowered by a mains electrical source and the sensors nodes are eachpowered by a battery source or another energy source (not mainselectrical source) to form the wireless asymmetric network. Thescheduled timing of causing the transmitter to be operable to transmitand causing the receiver to be operable to receive for each wirelessdevice of the nodes is determined based on a timing of communicationsbetween a hub and associated wireless device of the nodes.

By using the architectures illustrated in FIG. 6 or 7, nodes requiringlong battery life minimize the energy expended on communication andhigher level nodes in the tree hierarchy are implemented using availableenergy sources or may alternatively use batteries offering highercapacities or delivering shorter battery life. To facilitate achievementof long battery life on the battery operated terminal nodes,communication between those nodes and their upper level counterparts(hereafter referred to as lowest-level hubs) may be established suchthat minimal transmit and receive traffic occurs between thelowest-level hubs and the terminal nodes.

In one embodiment, the nodes spend most of their time (e.g., more than90% of their time, more than 95% of their time, approximately 98% ormore than 98% of their time) in a low-energy non-communicative state.When the node wakes up and enters a communicative state, the nodes areoperable to transmit data to the lowest-level hubs. This data mayinclude node identification information, sensor data, node statusinformation, synchronization information, localization information andother such information for the wireless sensor network.

In a deterministic manner related to the timing of the transmission, thenodes may also then operate so as to enable reception of data sent bythe lowest-level hubs or other communicative devices within the treenetwork architecture or tree and mesh network architecture. Since thetiming of the reception is related to the timing of the transmission,the terminal nodes do not expend excessive energy keeping their receiveradios of the receivers of the RF circuitry active in a receive mode.Additionally, transmit radios of the RF circuitry in the lowest-levelhubs, for example, are aware of when the receive radios of the terminalnodes are active based on the timing of the transmitted signals from theterminal nodes. Note that the lowest level hubs and other devices in thenetwork architecture can maintain their receive radios in an operablemode for receiving communications (e.g., receive mode) for a substantialfraction of time since they are not energy constrained. The data sent bythe hubs and received by the terminal nodes may include instructions,configuration information, node identification information, timinginformation, and other such information for the wireless sensor network.

The hubs may be physically implemented in numerous ways in accordancewith embodiments of the invention. FIG. 8A shows an exemplary embodimentof a hub implemented as an overlay 800 for an electrical power outlet inaccordance with one embodiment. The overlay 800 (e.g., faceplate)includes a hub 810 and a connection 812 (e.g., communication link,signal line, electrical connection, etc.) that couples the hub to theelectrical outlet 802. Alternatively (or additionally), the hub iscoupled to outlet 804. The overlay 800 covers or encloses the electricaloutlets 802 and 804 for safety and aesthetic purposes.

FIG. 8B shows an exemplary embodiment of an exploded view of a blockdiagram of a hub 820 implemented as an overlay for an electrical poweroutlet in accordance with one embodiment. The hub 820 includes a powersupply rectifier 830 that converts alternating current (AC), whichperiodically reverses direction, to direct current (DC) which flows inonly one direction. The power supply rectifier 830 receives AC from theoutlet 802 via connection 812 (e.g., communication link, signal line,electrical connection, etc.) and converts the AC into DC for supplyingpower to a controller circuit 840 via a connection 832 (e.g.,communication link, signal line, electrical connection, etc.) and forsupplying power to RF circuitry 850 via a connection 834 (e.g.,communication link, signal line, electrical connection, etc.). Thecontroller circuit 840 includes memory 842 or is coupled to memory thatstores instructions which are executed by processing logic 844 (e.g.,one or more processing units) of the controller circuit 840 forcontrolling operations of the hub for forming and monitoring thewireless asymmetrical network as discussed herein. The RF circuitry 850may include a transceiver or separate transmitter 854 and receiver 856functionality for sending and receiving bi-directional communicationsvia antenna(s) 852 with the wireless sensor nodes. The RF circuitry 850communicates bi-directionally with the controller circuit 840 via aconnection 834 (e.g., communication link, signal line, electricalconnection, etc.). The hub 820 can be a wireless control device 820 orthe controller circuit 840, RF circuitry 850, and antenna(s) 852 incombination may form the wireless control device as discussed herein.

FIG. 9A shows an exemplary embodiment of a hub implemented as a card fordeployment in a computer system, appliance, or communication hub inaccordance with one embodiment. The card 962 can be inserted into thesystem 960 (e.g., computer system, appliance, or communication hub) asindicated by arrow 963.

FIG. 9B shows an exemplary embodiment of a block diagram of a hub 964implemented as a card for deployment in a computer system, appliance, orcommunication hub in accordance with one embodiment. The hub 964includes a power supply 966 that provides power (e.g., DC power supply)to a controller circuit 968 via a connection 974 (e.g., communicationlink, signal line, electrical connection, etc.) and provides power to RFcircuitry 970 via a connection 976 (e.g., communication link, signalline, electrical connection, etc.). The controller circuit 968 includesmemory 961 or is coupled to memory that stores instructions which areexecuted by processing logic 963 (e.g., one or more processing units) ofthe controller circuit 968 for controlling operations of the hub forforming and monitoring the wireless asymmetrical network as discussedherein. The RF circuitry 970 may include a transceiver or separatetransmitter 975 and receiver 977 functionality for sending and receivingbi-directional communications via antenna(s) 978 with the wirelesssensor nodes. The RF circuitry 970 communicates bi-directionally withthe controller circuit 968 via a connection 972 (e.g., communicationlink, signal line, electrical connection, etc.). The hub 964 can be awireless control device 964 or the controller circuit 968, RF circuitry970, and antenna(s) 978 in combination may form the wireless controldevice as discussed herein.

FIG. 9C shows an exemplary embodiment of a hub implemented within anappliance (e.g., smart washing machine, smart refrigerator, smartthermostat, other smart appliances, etc.) in accordance with oneembodiment. The appliance 980 (e.g., smart washing machine) includes ahub 982.

FIG. 9D shows an exemplary embodiment of an exploded view of a blockdiagram of a hub 984 implemented within an appliance (e.g., smartwashing machine, smart refrigerator, smart thermostat, other smartappliances, etc.) in accordance with one embodiment. The hub includes apower supply 986 that provides power (e.g., DC power supply) to acontroller circuit 990 via a connection 996 (e.g., communication link,signal line, electrical connection, etc.) and provides power to RFcircuitry 992 via a connection 998 (e.g., communication link, signalline, electrical connection, etc.). The controller circuit 990 includesmemory 986 or is coupled to memory that stores instructions which areexecuted by processing logic 988 (e.g., one or more processing units) ofthe controller circuit 990 for controlling operations of the hub forforming and monitoring the wireless asymmetrical network as discussedherein. The RF circuitry 992 may include a transceiver or separatetransmitter 994 and receiver 995 functionality for sending and receivingbi-directional communications via antenna(s) 999 with the wirelesssensor nodes. The RF circuitry 992 communicates bi-directionally withthe controller circuit 990 via a connection 994 (e.g., communicationlink, signal line, electrical connection, etc.). The hub 984 can be awireless control device 984 or the controller circuit 990, RF circuitry992, and antenna(s) 999 in combination may form the wireless controldevice as discussed herein.

FIG. 10 illustrates a flow chart for a method of providingcommunications for a wireless asymmetric network architecture inaccordance with one embodiment. The operations of method 1000 may beexecuted by a wireless device, a wireless control device of a hub (e.g.,an apparatus), or system, which includes processing circuitry orprocessing logic. The processing logic may include hardware (circuitry,dedicated logic, etc.), software (such as is run on a general purposecomputer system or a dedicated machine or a device), or a combination ofboth. In one embodiment, a hub performs the operations of method 1000.

At operation 1002, processing logic of a hub having a wireless controldevice transmits communications including instructions and configurationinformation to a plurality of nodes. Other information including nodeidentification information, timing information, and other informationmay also be included in the transmitted communications. In one example,RF circuitry of the hub transmits and receives communications. Atoperation 1004, the hub receives communications from the plurality ofnodes each having a wireless device with a transmitter and a receiver(or transceiver) to enable bi-directional communications with the hub toform a wireless asymmetric network architecture. At operation 1006,processing logic (e.g., one or more processing units) of the hubdetermines a scheduled timing of causing the transmitter (or transmitterfunctionality of a transceiver) to be operable to transmit and causingthe receiver (or receiver functionality of a transceiver) to be operableto receive for each wireless device to reduce power consumption of thewireless devices of the plurality of nodes.

In one example, the hub is powered by a mains electrical source and theplurality of nodes are each powered by a battery source or anotherenergy source to form the wireless asymmetric network architecture.

In one embodiment, the scheduled timing of causing the transmitter (ortransmitter functionality of a transceiver) to be operable to transmitand causing the receiver (or receiver functionality of a transceiver) tobe operable to receive for each wireless device is determined based on atiming of communications between the hub and each wireless device of theplurality of nodes. In one example, the scheduled timing of causing thereceiver (or receiver functionality of a transceiver) to be operable toreceive for at least one wireless device of the nodes is determinedbased on a timing of a communication being transmitted from the at leastone wireless device to the hub.

In one example, the wireless asymmetric network architecture includes awireless tree asymmetric network architecture. In another example, thewireless asymmetric network architecture includes a wireless tree andmesh asymmetric network architecture.

In one embodiment, the hub may instruct one or more of the nodes toshift the timing of a future transmit/receive communications to avoidcollisions on the network. FIG. 11 illustrates a time sequence forshifting transmit and receive communications to avoid collisions of awireless asymmetric network architecture in accordance with oneembodiment. FIG. 11 illustrates transmit and receive time lines for ahub and nodes 1-4 of the wireless asymmetric network architecture.Initially, node 1 transmits a communication to the hub during a transmitwindow 1110 of the transmit timeline (TX). In this embodiment, the hublistens continuously as illustrated by the continuous receive window1108 of the hub. The hub then calculates a transmit window minus receivewindow separation of node 1 to determine a timing for a receive window1112 of the receive timeline (RX) of node 1. The hub sends acommunication to node 1 during transmit window 1114 of the hub and thereceive window 1112 of node 1 receives this communication. In otherwords, a receiver of RF circuitry (or receiver functionality of atransceiver) of wireless device of node 1 is operable to receive duringreceive window 1112 in order to receive communications.

In a similar manner, the hub communicates or transacts with node 2. Node2 transmits a communication to the hub during the transmit window 1116of the transmit timeline (TX) of node 2. The hub then calculates atransmit window minus receive window separation of node 2 to determine atiming for a receive window 1120 of the receive timeline (RX) of node 2.The hub sends a communication to node 2 during a transmit window 1118 ofthe hub and the receive window 1120 of node 2 receives thiscommunication.

The hub then detects a communication from node 3 during a transmitwindow 1122 of node 3 and at the same time or approximately the sametime also detects a communication from node 4 during a transmit window1124 of node 4. At this collision time 1130, the hub detects that acollision 1131 has occurred (e.g., when the hub detects that part or allof a transmission is unintelligible or irreversibly garbled). In otherwords, the communications from node 3 and node 4 combine to form anunintelligible transmission (e.g., an irreversibly garbled transmission)that is received by the hub at or near collision time 1130. The hub thencan calculate the next receive window for any of the nodes thattransmitted with the unintelligible or garbled transmission during theunintelligible or garbled transmit window (e.g., transmit windows 1122and 1124). In that next receive window (e.g., receive windows 1132 and1134) for nodes 3 and 4 or any further subsequent receive windows (e.g.,receive windows 1145 and 1147), the hub with transmit window 1126 caninstruct the colliding nodes (e.g., nodes 3 and 4) to shift theirrespective transmit and receive windows by different time delays or timeperiods as illustrated in FIG. 11. In this example, the time delay orshift 1150 from transmit window 1122 to transmit window 1144 of node 3is less than the time delay or shift 1152 from transmit window 1124 totransmit window 1146 of node 4 in order to avoid a collision based ontransmissions during transmit window 1144 and transmit window 1146.

This time delay or shift may be randomly determined using a randomnumber generator in each node, for example, or may be determined andinstructed by the hub. The hub may choose from available future windowsand offer them as a set to the colliding nodes. These colliding nodesmay then choose one of these randomly, for example. Once this selectionis made, the collision should be avoided for future windows. On theother hand, if a collision occurs again in the next window (for example,because two of the colliding nodes happened to choose the same timeshift), the process can be repeated until all collisions are avoided. Inthis way, the hub can arbitrate the operation of the entire networkwithout requiring significant complexity from the nodes, thus reducingthe energy required for operation of the nodes.

FIG. 12 illustrates a method of arbitration and collision avoidance forcommunications in a wireless asymmetric network architecture inaccordance with one embodiment. The operations of method 1200 may beexecuted by a wireless device, a wireless control device of a hub (e.g.,an apparatus), or system, which includes processing circuitry orprocessing logic. The processing logic may include hardware (circuitry,dedicated logic, etc.), software (such as is run on a general purposecomputer system or a dedicated machine or a device), or a combination ofboth. In one embodiment, a hub performs the operations of method 1200.

At operation 1202, a receiver (e.g., RF circuitry, receiverfunctionality of a transceiver) of the hub detects a communication(e.g., transmission) from at least one node of a plurality of nodeswithin the wireless asymmetric network architecture. Each node includesor is a wireless device with a transmitter and a receiver (ortransmitter and receiver functionality of a transceiver) to enablebi-directional communications with the hub to form the wirelessasymmetric network architecture. At operation 1204, processing logic ofthe hub determines whether at least a portion (e.g., 25%, 50%, 75%) ofthe communication is unintelligible (e.g., garbled, distorted) toprocessing circuitry of the hub or processing circuitry connected to thehub potentially based on interference from another communication or RFsource.

At operation 1206, when the communication is determined to beintelligible, the processing logic of the hub determines anidentification of the node that transmitted the communication and alsodetermines a next or subsequent receive window(s) for the transmittingnode. At operation 1208, a transmitter (or transmitter functionality ofa transceiver) of the hub transmits a communication to this node duringthe determined next or subsequent receive window(s) if necessary orappropriate.

At operation 1210, when at least a portion of the communication isdetermined to be unintelligible, the processing logic of the hubdetermines whether a collision of communications transmitted atapproximately the same time from different nodes has likely occurred(e.g., approximately equal to or greater than 50 percent chance ofcollision occurring). If so, then the processing logic of the hubcalculates a next or subsequent receive windows for the colliding nodesat operation 1212. During receive windows of the colliding nodes, thehub (e.g., transmitter of the hub, transmitter functionality of atransceiver of the hub) transmits communications to the colliding nodeswith instructions for the nodes to shift a next transmit window bydiffering time periods or randomly determined time periods. For example,a first node is instructed based on a first communication from the hubto shift a next transmit window by a first time period while a secondnode is instructed by a second communication from the hub to shift anext transmit window by a second time period. In this example, the firstand second periods are sufficiently different to avoid collisions fromfuture transmissions of the first and second nodes.

If the processing logic of the hub determines at operation 1210 that acollision of communications transmitted at approximately the same timefrom different nodes has likely not occurred, then at operation 1216 theprocessing logic of the hub determines a next or subsequent receivewindow for the node that transmitted a communication with at least aportion of the communication being unintelligible to processingcircuitry of the hub or processing circuitry coupled to the hub. Atoperation 1218, during the calculated next or subsequent receive windowof the node, the processing logic of the hub sends a communication fromthe hub to the node with the communication requesting a repeattransmission of the earlier communication from the node.

In one embodiment, an apparatus (e.g., hub, wireless control device,etc.) for providing a wireless asymmetric network architecture includesa memory (e.g., memory 842, memory 961, memory 986, memory 1886) forstoring instructions, processing logic (e.g., one or more processingunits, processing logic 844, processing logic 963, processing logic 988,processing logic 1888) to execute instructions to establish and controlcommunications in the wireless asymmetric network architecture, andradio frequency (RF) circuitry to transmit and receive communications inthe wireless asymmetric network architecture. The RF circuitry (e.g., RFcircuitry 850, RF circuitry 970, RF circuitry 992, RF circuitry 1890) totransmit communications to a plurality of nodes each having a wirelessdevice with a transmitter and a receiver (or transmitter and receiverfunctionality of a transceiver) to enable bi-directional communicationswith the RF circuitry of the hub in the wireless asymmetric networkarchitecture. The processing logic (e.g., one or more processing units)are configured to execute instructions to determine a transmit windowfor a transmitter and a receive window for a receiver of each wirelessdevice (e.g., sensor nodes, terminal nodes) that transmit acommunication to the apparatus and provide anti-collision features toavoid collisions of the communications received from the wirelessdevices.

In one example, the apparatus is powered by a mains electrical sourceand the plurality of nodes are each powered by a battery source oranother energy source (not mains electrical source) to form the wirelessasymmetric network.

In one embodiment, the processing logic (e.g., one or more processingunits) of the hub are configured to execute instructions to determinewhether a collision has occurred for a communication received from afirst node and calculate next or subsequent receive windows for thefirst node and a second node if a collision of communications from thefirst and second nodes has occurred.

In one example, the processing logic (e.g., one or more processingunits) of the hub are configured to execute instructions to transmit acommunication to each of the first and second nodes with eachcommunication for each node to cause a shift of a next transmit windowfor each node by differing time periods or randomly determined timeperiods during receive windows of the first and second nodes.

The processing logic (e.g., one or more processing units) of the hub areconfigured to execute instructions to generate at least one randomnumber and to shift at least one of a future transmit window or a futurereceive window for at least one node based on the at least one randomnumber when the collision has occurred for communications received fromthe first and second nodes. In one example, the wireless asymmetricnetwork architecture is implemented within a building or near thebuilding in order to secure and monitor conditions within or near thebuilding.

In one embodiment, additional communication may be provided between thehubs at the various upper levels of the tree network architecture ortree and mesh network architecture. This communication may includetransfer of data received form the terminal nodes or data to be sent tothe terminal nodes, configuration information, timing information, huband/or node identification information, and other such.

The communication between hubs and nodes as discussed herein may beachieved using a variety of means, including but not limited to directwireless communication using radio frequencies, Powerline communicationachieved by modulating signals onto the electrical wiring within thehouse, apartment, commercial building, etc., WiFi communication usingsuch standard WiFi communication protocols as 802.11a, 802.11b, 802.11n,802.11ac, and other such Wifi Communication protocols as would beapparent to one of ordinary skill in the art, cellular communicationsuch as GPRS, EDGE, 3G, HSPDA, LTE, and other cellular communicationprotocols as would be apparent to one of ordinary skill in the art,Bluetooth communication, communication using well-known wireless sensornetwork protocols such as Zigbee, and other wire-based or wirelesscommunication schemes as would be apparent to one of ordinary skill inthe art.

The implementation of the radio-frequency communication between theterminal nodes and the hubs may be implemented in a variety of ways. Inone embodiment, the communication may be achieved using ultra-wide-bandcommunication (UWB). UWB has several advantages. For example, UWBcommunication offers better immunity to problems associated withmulti-path interference. In narrow-band systems, it is well-known thattime-delayed signals reflecting off surfaces added to line-of-sightsignals, for example, can cause degradation of signal strength andintegrity. In UWB, on the other hand, since pulse widths are short,degradation is generally suppressed. UWB also offers better channelutilization, which is helpful in a wireless sensor network with multiplesimultaneously communicating nodes. UWB also offers better penetrationproperties, such that walls, etc. present in indoor environments do notdegrade network performance as significantly as they do for manynarrow-band networks. UWB also allows for a much simpler radioarchitecture, with less RF components such as inductors, capacitors,etc. This is advantageous in low-power environments since powering ofthese components typically increases overall power consumption. Thus,UWB has advantages in terms of improved battery life for batteryoperated UWB radios in terminal nodes.

Furthermore, UWB allows implementation of sensor localization in arelatively straightforward manner. FIG. 13 illustrates a flow chart fora method of providing implementation of sensor localization for awireless asymmetric network architecture in accordance with oneembodiment. The operations of method 1300 may be executed by a wirelessdevice, a wireless control device of a hub (e.g., an apparatus), orsystem, which includes processing circuitry or processing logic. Theprocessing logic may include hardware (circuitry, dedicated logic,etc.), software (such as is run on a general purpose computer system ora dedicated machine or a device), or a combination of both. In oneembodiment, a hub performs the operations of method 1300.

At operation 1301, the hub having radio frequency (RF) circuitry and atleast one antenna transmits communications to a plurality of sensornodes in the wireless asymmetric network architecture. At operation1302, the RF circuitry and at least one antenna of the hub receivescommunications from the plurality of sensor nodes each having a wirelessdevice with a transmitter and a receiver to enable bi-directionalcommunications with the RF circuitry of the hub in the wirelessasymmetric network architecture. At operation 1303, the processing logic(e.g., one or more processing units) of the hub determine locationinformation (e.g., precise location information) for the plurality ofsensor nodes based on receiving communications from each sensor node.The level of precision required may be chosen based on the needs of theapplication for which the sensor network is deployed. For example,location precision may be better than 1 meter (m) in any direction, suchthat in a typical indoor or near-indoor environment, the approximateposition of the sensors are known, and there is little or no overlap inthe certainly of position of any two or more sensors. In applicationsrequiring greater precision, location precision of better than 10centimeters (cm) can be obtained, such that the accurate position ofeach sensor node is known.

In one example, the hub is powered by a mains electrical source and theplurality of sensor nodes are each powered by a battery source oranother energy source (not mains electrical source) to form the wirelessasymmetric network architecture.

In one example, the one or more processing units of the hub determinelocation information for the plurality of sensor nodes based on at leastone of angle of arrival information, signal strength information, andtime of arrival information for the communications received from theplurality of sensor nodes.

In another example, the one or more processing units determine locationinformation for the plurality of sensor nodes based on angle of arrivalinformation for determining an angle of arrival with a strongestsignaling component and combined with information to identify a shortestdirect path in a multi-path environment, which is determined from timeof arrival information, for the communications from the plurality ofsensor nodes.

In one example, the wireless asymmetric network architecture includes atleast one of a wireless tree asymmetric network architecture or awireless tree and mesh asymmetric network architecture.

In one embodiment, the at least one antenna of the hub transmitsultra-wide band (UWB) communications to the plurality of sensor nodesand to receive UWB communications from the plurality of sensor nodes.

Hubs receiving UWB transmissions from nodes, for example, can determinethe location of nodes using angle of arrival (AOA), signal strength (SS)and/or Time of Arrival (TOA) information. AOA information can bedetermined using multiple antennas on the hub to enable determination ofthe angle of arrival with the strongest signal component. Combined withinformation to identify the most direct path, which can be determinedfrom TOA, sensor location can be established. Due to the short pulsesused in UWB, accuracy of TOA can be high, particularly in environmentswith multiple paths. Similarly, SS information can be used to estimatesensor distance from nodes, and, combined with AOA, can provide sensorlocalization. In one example, the overall architecture for UWB-basedsensor localization is shown in FIG. 14.

FIG. 14 illustrates use of multiple antennas on an apparatus (e.g., hub)and a multipath environment to enable sensor localization in accordancewith one embodiment. The environment 1400 includes walls 1330, 1331, and1332. A hub 1310 includes antennas 1311, 1312, and 1313. The sensor node1 includes an antenna 1321 and the sensor node 2 includes an antenna1322. The hub 1310 if receiving transmissions 1340-1347 (e.g., UWBtransmissions) from nodes 1 and 2, for example, can determine thelocation of nodes 1 and 2 using angle of arrival (AOA), signal strength(SS) and/or Time of Arrival (TOA) information. The effect of multiplepaths (e.g., based on reflections from walls or other objects such as afirst path for transmission 1346 and a second path for transmission 1347that is reflected by wall 1332) can be accommodated due to short UWBpulses as illustrated by the 2 peaks of the signal 1348 versus time1349. The signal 1348 represents a combination of transmissions 1346 and1347. A first peak 1334 represents the transmission 1346 while a secondpeak 1336 represents the transmission 1347. AOA information can bedetermined using multiple antennas 1311-1313 on the hub 1310 to enabledetermination of the angle of arrival with the strongest signalcomponent. Combined with information to identify the most direct path,which can be determined from TOA, sensor location of nodes 1 and 2 canbe established. Due to the short pulses used in UWB, accuracy of TOA canbe high, particularly in environments with multiple paths. Similarly, SSinformation can be used to estimate sensor distance from nodes, and,combined with AOA, can provide sensor localization.

In one embodiment, an apparatus (e.g., hub 610, hub 710, hub 720, hub782, hub n, hub 820, hub 964, hub 984, hub 1310, hub 1882) for providinga wireless asymmetric network architecture includes a memory (e.g.,memory 842, memory 961, memory 986, memory 1886) for storinginstructions, processing logic (e.g., one or more processing units,processing logic 844, processing logic 963, processing logic 988,processing logic 1888) of the hub to execute instructions to establishand control communications in a wireless asymmetric networkarchitecture, and radio frequency (RF) circuitry (e.g., RF circuitry850, RF circuitry 970, RF circuitry 992, RF circuitry 1890) includingmultiple antennas (e.g., antenna(s) 852, antenna(s) 978, antenna(s) 999,antennas 1311, 1312, and 1313) to transmit and receive communications inthe wireless asymmetric network architecture. The RF circuitry andmultiple antennas to transmit communications to a plurality of sensornodes (e.g., node 1, node 2) each having a wireless device with atransmitter and a receiver (or transmitter and receiver functionality ofa transceiver) to enable bi-directional communications with the RFcircuitry of the apparatus in the wireless asymmetric networkarchitecture. The processing logic (e.g., one or more processing units)are configured to execute instructions to determine location informationfor the plurality of sensor nodes based on receiving communications fromeach sensor node.

In one embodiment, the apparatus is powered by a mains electrical sourceand the plurality of sensor nodes are each powered by a battery sourceor another energy source (not mains electrical source) to form thewireless asymmetric network.

In one embodiment, the processing logic (e.g., one or more processingunits) are configured to execute instructions to determine locationinformation for the plurality of sensor nodes based on at least one ofangle of arrival information, signal strength information, and time ofarrival information for the communications from the plurality of sensornodes.

In one embodiment, the processing logic (e.g., one or more processingunits) are configured to execute instructions to determine locationinformation for the plurality of sensor nodes based on angle of arrivalinformation for determining an angle of arrival with a strongestsignaling component and combined with information to identify a shortestdirect path in a multi-path environment, which is determined from timeof arrival information, for the communications from the plurality ofsensor nodes.

In one example, the wireless asymmetric network architecture includes atleast one of a wireless tree asymmetric network architecture or awireless tree and mesh asymmetric network architecture.

In one embodiment, the multiple antennas of the RF circuitry to transmitultra-wide band (UWB) communications to the plurality of sensor nodesand to receive UWB communications from the plurality of sensor nodes.

In an alternative embodiment, multiple hubs can be used tosimultaneously receive data from sensor nodes. In this application, bytriangulating from distances measured via SS or TOA estimates, locationof sensors can be established without need for AOA determination. Thisexample is shown in FIG. 15.

FIG. 15 illustrates use of multiple hubs each having a single antenna toachieve localization of sensors in accordance with one embodiment. Theenvironment 1350 includes walls 1370, 1371, and 1372. A system 1354includes a hub 1360 having an antenna 1361, a hub 1362 having an antenna1363, and a hub 1364 having an antenna 1365. The hubs are synchronizedwith each other. The sensor node 1382 includes an antenna 1383 and thesensor node 1380 includes an antenna 1381. The sensor node 1380transmits transmissions 1370-1372 to the hubs 1360, 1362, and 1364,respectively as illustrated in FIG. 15. The sensor node 1382 transmitstransmissions 1373-1375 to the hubs 1360, 1362, and 1364, respectivelyas illustrated in FIG. 15. Time of arrival information at multiple hubscan be used to map location of the nodes 1380 and 1382.

In one embodiment, a system (e.g., system 1350) for providing a wirelessasymmetric network includes a first hub (e.g., hub 1360) havingprocessing logic (e.g., one or more processing units) and a firstantenna (e.g., antenna 1361) for transmitting and receivingcommunications in the wireless asymmetric network. A second hub (e.g.,hub 1362) includes processing logic (e.g., one or more processing units)and a second antenna (e.g., antenna 1361) for transmitting and receivingcommunications in the wireless asymmetric network. The system alsoincludes a plurality of sensor nodes (e.g., nodes 1380 and 1382) eachhaving a wireless device with a transmitter and a receiver (ortransmitter and receiver functionality of a transceiver) to enablebi-directional communications with the first and second hubs in thewireless asymmetric network architecture. The processing logic (e.g.,processing logic of controller circuit 840, 968, 990) of the first andsecond hubs are configured to execute instructions to determine locationinformation for the plurality of sensor nodes based on receivingcommunications from each sensor node.

In one example, the first hub is powered by a mains electrical sourceand the plurality of sensor nodes are each powered by a battery sourceto form the wireless asymmetric network.

In one embodiment, the first and second hubs are synchronized with eachother and share location information of the plurality of sensors nodes.

In one embodiment, the processing logic (e.g., one or more processingunits) of the first and second hubs are configured to executeinstructions to determine location information for the plurality ofsensor nodes based on triangulating from distances measured via time ofarrival information that is associated with the received communications.

In another embodiment, the processing logic (e.g., one or moreprocessing units) of the first and second hubs are configured to executeinstructions to determine location information for the plurality ofsensor nodes based on triangulating from distances measured via strengthof signal information that is associated with the receivedcommunications.

In one example, the wireless asymmetric network architecture includes awireless tree asymmetric network architecture. In another example, thewireless asymmetric network architecture includes a wireless tree andmesh asymmetric network architecture.

In one embodiment, the processing logic (e.g., one or more processingunits) of the second hub are configured to execute instructions to sendcommunications to the first hub and to receive communications from thefirst hub for controlling and monitoring the wireless asymmetric networkarchitecture.

In one embodiment, the first antenna of the first hub and the secondantenna of the second hub transmit ultra-wide band (UWB) communicationsto the plurality of sensor nodes and to receive UWB communications fromthe plurality of sensor nodes.

In one embodiment, a system for providing a wireless asymmetric networkarchitecture includes power management features for reducing powerconsumption of sensor nodes. The system (e.g., system 700) includes afirst hub (e.g., hub 710, hub 820, hub 964, hub 984, hub 1882, etc.)having a wireless control device that is configured to controlcommunications and power consumption in the wireless asymmetric networkarchitecture and a first plurality of sensor nodes (e.g., sensor nodes731, 741, 751; sensor nodes 761, 771; sensor nodes 788, 792; sensornodes n, n+1; etc.) each having at least one sensor and a wirelessdevice with a transmitter and a receiver (or transmitter and receiverfunctionality of a transceiver) to enable bi-directional communicationswith the wireless control device of the first hub in the wirelessasymmetric network architecture. The wireless control device of thefirst hub is configured to determine a scheduled timing of operatingeach sensor node during a first time period that is close in time withrespect to a transmit window of the transmitter (or transmitterfunctionality of a transceiver) and during a second time period that isclose in time with respect to a receive window of the receiver (orreceiver functionality of a transceiver) for each wireless device toreduce power consumption of the wireless devices of the first pluralityof sensor nodes.

In one example, the first hub is powered by a mains electrical sourceand the first plurality of sensor nodes are each powered by a batterysource or another energy source (not mains electrical source) to formthe wireless asymmetric network architecture.

In one embodiment, the wireless control device is configured todetermine a scheduled timing of the transmit window of the transmitter(or transmitter functionality of a transceiver) and the receive windowof the receiver (or receiver functionality of a transceiver) for eachwireless device based on a timing of receiving a communication from eachwireless device of the plurality of sensor nodes.

In one embodiment, each sensor node operates at a first powerconsumption level for the first and second time periods. For example,each sensor node can operate at a second power consumption level whenoutside of the first and second time periods. The first powerconsumption level has more power consumption than the second powerconsumption level in this example.

In a more specific embodiment, each sensor node operates at a firstclock speed for the first and second time periods. Each sensor nodeoperates at a second clock speed when outside of the first and secondtime periods. The second clock speed can be a reduced clock speed toreduce power consumption of each sensor node in comparison to the firstclock speed.

In one embodiment, at least one sensor node operates with a batterysource that includes a rechargeable battery designed for recharging. Theat least one sensor node may also include a capacitor or is coupled to acapacitor to store energy from energy harvesting that is used to avoiddeep discharge of the battery source by recharging the rechargeablebattery.

In another embodiment, at least one sensor node operates with a batterysource that includes a primary cell that is not intended for recharging.The at least one sensor node includes a capacitor or is coupled to acapacitor to store energy from energy harvesting to trickle charge theprimary cell thus increasing effective battery capacity by compensatingfor energy drawn from the battery source during operation, or lost dueto self-discharge of the battery source.

In one embodiment, a second hub (e.g., hub 720, hub 782, hub n, hub 820,hub 964, hub 984, hub 1882, etc.) includes a wireless control devicethat is configured to control communications and power consumption inthe wireless asymmetric network architecture and a second plurality ofsensor nodes (e.g., sensor nodes 731, 741, 751; sensor nodes 761, 771;sensor nodes 788, 792; sensor nodes n, n+1; etc.) each having at leastone sensor and a wireless device with a transmitter and a receiver (ortransmitter and receiver functionality of a transceiver) to enablebi-directional communications with the wireless control device of thesecond hub in the wireless asymmetric network architecture. In oneexample, the wireless control device is configured to determine ascheduled timing of operating each sensor node during a third timeperiod that is close in time with respect to a transmit window of thetransmitter (or transmitter functionality of a transceiver) and during afourth time period that is close in time with respect to a receivewindow of the receiver (or receiver functionality of a transceiver) foreach wireless device to reduce power consumption of the wireless devicesof the second plurality of sensor nodes.

In one example, the third time period is approximately the same timeperiod as the transmit window and the fourth time period isapproximately the same time period as the receive window. In anotherexample, the third time period starts just prior to a time period of thetransmit window and completes just after the transmit window. The thirdtime period may be 1-10% longer than the time period of the transmitwindow. The fourth time period starts just prior to a time period of thereceive window and completes just after the receive window. The fourthtime period may be 1-10% longer than the time period of the receivewindow.

In one embodiment, the wireless asymmetric network architecture includesa wireless tree asymmetric network architecture. In another embodiment,the wireless asymmetric network architecture includes a wireless treeand mesh asymmetric network architecture.

In one embodiment for reduced power consumption based on use of a higherfrequency band, the wireless control device of the first hub includesradio frequency (RF) circuitry that operates at a frequency band greaterthan 2.4 GigaHertz (GHz). The transmitter and the receiver (ortransmitter and receiver functionality of a transceiver) of eachwireless device of the first plurality of nodes also operates at afrequency band greater than 2.4 GHz in order to minimize a third timeperiod for causing RF circuitry of the transmitter to be operable and afourth time period for causing RF circuitry of the receiver to beoperable for each wireless device to reduce power consumption of thewireless devices of the first plurality of nodes.

In another embodiment, the RF circuitry of the first hub operates at afrequency band greater than 5 GHz. The transmitter and the receiver (ortransmitter and receiver functionality of a transceiver) of eachwireless device of the first plurality of nodes also operates at afrequency band greater than 5 GHz in order minimize the third timeperiod for causing RF circuitry of the transmitter and the fourth timeperiod for causing RF circuitry of the receiver for each wireless deviceto reduce power consumption of the wireless devices of the firstplurality of nodes.

In one embodiment, an apparatus (e.g., hub 610, hub 720, hub 782, hub n,hub 820, hub 964, hub 984, hub 1882, etc.) for providing a wirelessasymmetric network architecture with power management features includesa memory (e.g., memory 842, memory 961, memory 986, memory 1886) forstoring instructions, processing logic (e.g., one or more processingunits, processing logic 844, processing logic 963, processing logic 988,processing logic 1888) to execute instructions to establish and controlcommunications in the wireless asymmetric network architecture, andradio frequency (RF) circuitry (e.g., RF circuitry 850, RF circuitry970, RF circuitry 992, RF circuitry 1890) to transmit and receivecommunications in the wireless asymmetric network architecture. The RFcircuitry transmits communications to a plurality of sensor nodes eachhaving at least one sensor and a wireless device with a transmitter anda receiver (or transmitter and receiver functionality of a transceiver)to enable bi-directional communications with the RF circuitry of theapparatus in the wireless asymmetric network architecture. The one ormore processing units execute instructions to determine a scheduledtiming of operating at least one sensor node during a first time periodthat is close in time with respect to a transmit window of thetransmitter (or transmitter functionality of a transceiver) and during asecond time period that is close in time with respect to a receivewindow of the receiver (or receiver functionality of a transceiver) forat least one wireless device to reduce power consumption of the at leastone wireless device of the first plurality of sensor nodes.

In one example, the apparatus is powered by a mains electrical sourceand the plurality of sensor nodes are each powered by a battery sourceor another energy source (not mains electrical source) to form thewireless asymmetric network architecture.

In one embodiment, the processing logic (e.g., one or more processingunits) execute instructions to determine a scheduled timing of atransmit window of the transmitter and a receive window of the receiverfor the at least one wireless device based on a timing of receiving acommunication from the at least one wireless device of the plurality ofsensor nodes.

In one embodiment, the at least one wireless device of at least onesensor node operates at a first power consumption level for the firstand second time periods. The at least one sensor node operates at asecond power consumption level when outside of the first and second timeperiods. In this example, the first power consumption level has morepower consumption than the second power consumption level.

In a more specific embodiment, the at least one wireless device of atleast one sensor node operates at a first clock speed for the first andsecond time periods. The at least one sensor node operates at a secondclock speed when outside of the first and second time periods. Thesecond clock speed is a reduced clock speed to reduce power consumptionof the at least sensor node in comparison to the first clock speed.

In one example, the wireless asymmetric network architecture includes atleast one of a wireless tree asymmetric network architecture or awireless tree and mesh asymmetric network architecture.

FIG. 16 illustrates a flow chart for a method of providing a wirelessasymmetric network architecture with a hub having power managementfeatures in accordance with one embodiment. The operations of method1600 may be executed by a wireless device, a wireless control device ofa hub (e.g., an apparatus), or system, which includes processingcircuitry or processing logic. The processing logic may include hardware(circuitry, dedicated logic, etc.), software (such as is run on ageneral purpose computer system or a dedicated machine or a device), ora combination of both. In one embodiment, a hub performs the operationsof method 1600.

At operation 1602, a method for reducing power consumption in a wirelessasymmetric network architecture includes receiving, with radio frequency(RF) circuitry of a hub, communications from a plurality of sensor nodeseach having a wireless device with a transmitter and a receiver (ortransmitter and receiver functionality of a transceiver) to enablebi-directional communications with the hub to form the wirelessasymmetric network architecture. At operation 1604, the processing logicof the hub determines a scheduled timing of operating at least onesensor of each sensor node during a first time period that is close intime with respect to a transmit window of the transmitter (ortransmitter functionality of a transceiver) and during a second timeperiod that is close in time with respect to a receive window of thereceiver (or receiver functionality of a transceiver) for each wirelessdevice to reduce power consumption of the wireless devices of theplurality of sensor nodes.

In one example, the hub is powered by a mains electrical source and theplurality of nodes are each powered by a battery source or anotherenergy source (not mains electrical source) to form the wirelessasymmetric network architecture.

At operation 1606, the processing logic of the hub determines ascheduled timing of the transmit window of the transmitter and thereceive window of the receiver for each wireless device based on atiming of receiving a communication from each wireless device of theplurality of sensor nodes.

In one embodiment, each sensor node operates at a first powerconsumption level for the first and second time periods. Each sensornode operates at a second power consumption level when outside of thefirst and second time periods. In this example, the first powerconsumption level has more power consumption than the second powerconsumption level.

In a more specific embodiment, each sensor node operates at a firstclock speed for the first and second time periods. Each sensor nodeoperates at a second clock speed when outside of the first and secondtime periods. In this example, the second clock speed is a reduced clockspeed to reduce power consumption of each sensor node in comparison tothe first clock speed.

In one embodiment, the wireless asymmetric network architecture includesa wireless tree asymmetric network architecture. In another embodiment,the wireless asymmetric network architecture includes a wireless treeand mesh asymmetric network architecture.

Embodiments of the present invention provide improvements in the overallbattery life offered by nodes of a wireless sensor network in indoor andnearby environments. In one embodiment, this may additionally beachieved by implementing energy harvesting in the battery operatedterminal nodes, any battery operated node, or any node with analternative energy source with no connection to electrical mains. Energyharvesting may be achieved using vibrational harvesting, light energyharvesting, thermal energy harvesting, wireless energy harvesting and/orother such energy harvesting techniques. In vibrational energyharvesting, vibrations in the environment of the sensor nodes could beused to stimulate motion of a mass within the sensor node system. Thiscould be used to generate electrical energy, for example, by causing thedeflection of a piezo-electric structure, or by moving a magnet relativeto a coil. The resulting electrical energy could then be stored in acapacitor, or could be used to charge a battery within the sensor node.

FIG. 19 illustrates a block diagram of a vibrational energy harvestingsystem for providing a supplemental energy source to a sensor node inaccordance with one embodiment. A vibrational energy harvester circuit1910 may include a piezoelectric generator or an electromagnetic proofmass system, in which vibration causes the motion of a coil relative toa magnet and this is used to generate electrical power, which isprovided to a rectifier regulator power conditioning block 1920. Thisblock 1920 includes one or more circuits for the rectifying, regulating,and power conditioning functionality. This block 1920 receives theirregular and/or alternating current generated by the harvester via aconnection 1912 (e.g., communication link, signal line, electricalconnection, etc.), rectifies and filters the irregular and/oralternating current, and regulates it to a suitable voltage for usewithin the sensor node. The output of the block 1920 is then provided tocapacitive energy storage block 1930 via a connection 1922. Thecapacitive energy storage block 1930 includes at least one storagecapacitor, which stores the harvested energy as a supplemental energysource for use by sensing and communication circuitry 1960 of a sensornode. The sensing and communication circuitry 1960 includes sensingcircuitry 1961 and communication circuitry 1962. A power selector block1940 having a selecting mechanism is then used to select harvested powerfrom the at least one storage capacitor when available via a connection1932, or use power supplied from a primary cell battery source 1950 viaa connection 1952. In this manner, energy harvesting may be used inconjunction with a non-rechargeable battery (i.e., the primary cellbattery source 1950) to supplement battery-provided power for sustainingoperations of the sensor node including operations of the sensing andcommunication circuitry 1960.

Alternatively, in another embodiment, the system could be configured touse a rechargeable battery; in this case, the harvester may bealternatively used to charge the battery. FIG. 20 illustrates a blockdiagram of a vibrational energy harvesting system for charging arechargeable battery of a sensor node in accordance with anotherembodiment. A vibrational energy harvester circuit 2010 may include apiezoelectric generator or an electromagnetic proof mass system, inwhich vibration causes the motion of a coil relative to a magnet andthis is used to generate electrical power, which is provided to arectifier regulator power conditioning battery charger block 2020. Thisblock 2020 includes one or more circuits for the rectifying, regulating,power conditioning, and battery charger functionality. This block 2020receives the irregular and/or alternating current generated by theharvester via a connection 2012 (e.g., communication link, signal line,electrical connection, etc.), rectifies and filters the irregular and/oralternating current, and regulates it to a suitable voltage for usewithin the sensor node. The output of the block 2020 is then provided toa rechargeable cell battery source 2030 via a connection 2022. Therechargeable cell battery source 2030 provides power to the sensing andcommunication 2060 of a sensor node via a connection 2032. The sensingand communication circuitry 2060 includes sensing circuitry 2061 andcommunication circuitry 2062. In this manner, energy harvesting may beused to charge a rechargeable battery (i.e., the rechargeable cellbattery source 2030) to supplement battery-provided power for sustainingoperations of the sensor node including operations of the sensing andcommunication circuitry 2060.

In light energy harvesting, photovoltaic cells could be used to produceelectrical energy from incident light, including sunlight, indoorlighting, outdoor artificial lighting, and other such lighting sources.The resulting electrical energy could then be stored in a capacitor, orcould be used to charge a battery within a sensor node. FIG. 21illustrates a block diagram of a photovoltaic energy harvesting systemfor charging a rechargeable battery of a sensor node in accordance withone embodiment. A photovoltaic energy harvesting circuit 2110 includes aphotovoltaic generator, which may contain one or more photovoltaic cellsfor generating electrical power. The photovoltaic energy harvestingcircuit 2110 is coupled to a power conditioner battery charger block2120 via a connection 2112. The output electrical power of the circuit2110 is conditioned by a power conditioner of the power conditionerbattery charger block 2120 and used to charge a rechargeable batterycell 2130. The power conditioner battery charger block 2120 is coupledto the rechargeable battery cell 2130 via a connection 2122. Therechargeable battery cell 2130 in turn then provides power for theoperation of the sensing and communication circuitry 2140 of the sensornode via a connection 2132. The sensing and communication circuitry 2140includes sensing circuitry 2141 and communication circuitry 2142. Inthis manner, the battery life may be extended by exploiting energyharvesting. For example, energy harvesting may be used to compensate forthe self-discharge of the battery source. In another example, energyharvesting may be used to trickle charge a cell that is normally notdesigned for secondary cell usage.

In thermal energy harvesting, electrical energy could be produced byusing a thermoelectric device to convert available thermal energy intoelectrical energy. This could then be stored in a capacitor, or could beused to charge a battery within the sensor node.

In wireless energy harvesting, incident radio-frequency energy could beextracted using an antenna, rectified, and then used to charge acapacitor or battery within the sensor node. The source of RF energycould be WiFi at 2.4 Gz or 5 GHz, DECT at 1.8 GHz or any other RF signalavailable for extraction at the sensor node. In one embodiment, the RFsignal could be intentionally supplied to the terminal nodes by hubs orby RF generators placed within the physical coverage region of thewireless sensor network.

In one embodiment, the energy from energy harvesting could be stored ina capacitor, which could be used to supplement energy drawn from thebattery during operation. In another embodiment, the energy from theenergy harvesting could be used to re-charge the battery. In thisembodiment, the battery could be either a rechargeable battery designedspecifically for recharging, or could be a primary cell, typically notintended for recharging. In embodiments with rechargeable batteries,energy harvesting could be used to avoid deep discharge of the battery,thus prolonging battery life.

In embodiments with primary cells, harvested energy could be used totrickle charge the battery, thus increasing effective battery capacity,for example, by compensating for energy drawn from the battery duringoperation, or lost due to self-discharge of the battery. In oneembodiment, trickle charging of the battery could be kept at asufficiently low level to avoid damage to the battery. In anotherembodiment, pulsed charging could be used to prevent damage to thebattery.

Various batteries could be used in the wireless sensor nodes, includinglithium-based chemistries such as Lithium Ion, Lithium Polymer, LithiumPhosphate, and other such chemistries as would be apparent to one ofordinary skill in the art. Additional chemistries that could be usedinclude Nickel metal hydride, standard alkaline battery chemistries,Silver Zinc and Zinc Air battery chemistries, standard Carbon Zincbattery chemistries, lead Acid battery chemistries, or any otherchemistry as would be obvious to one of ordinary skill in the art.

The present invention also relates to an apparatus for performing theoperations described herein. This apparatus may be specially constructedfor the required purposes, or it may comprise a general purpose computerselectively activated or reconfigured by a computer program stored inthe computer. Such a computer program may be stored in a computerreadable storage medium, such as, but not limited to, any type of diskincluding floppy disks, optical disks, CD-ROMs, and magnetic-opticaldisks, read-only memories (ROMs), random access memories (RAMs), EPROMs,EEPROMs, magnetic or optical cards, or any type of media suitable forstoring electronic instructions.

The algorithms and displays presented herein are not inherently relatedto any particular computer or other apparatus. Various general purposesystems may be used with programs in accordance with the teachingsherein, or it may prove convenient to construct a more specializedapparatus to perform the required method operations.

FIG. 17 illustrates a block diagram of a sensor node in accordance withone embodiment. The sensor node 1700 includes a power source 1710 (e.g.,energy source, battery source, primary cell 1950, rechargeable cell2030, rechargeable cell 2130, etc.) that provides power (e.g., DC powersupply) to a controller circuit 1720 via a connection 1774 (e.g.,communication link, signal line, electrical connection, etc.), providespower to RF circuitry 1770 via a connection 1776 (e.g., communicationlink, signal line, electrical connection, etc.), and provides power tosensing circuitry 1740 via a connection 1746 (e.g., communication link,signal line, electrical connection, etc.). The controller circuit 1720includes memory 1761 or is coupled to memory that stores instructionswhich are executed by processing logic 1763 (e.g., one or moreprocessing units) of the controller circuit 1720 for controllingoperations of the sensor node for forming and monitoring the wirelessasymmetrical network as discussed herein. The RF circuitry 1770 (e.g.,communication circuitry) may include a transceiver or separatetransmitter 1775 and receiver 1777 functionality for sending andreceiving bi-directional communications via antenna(s) 1778 with thehub(s) and optional wireless sensor nodes. The RF circuitry 1770communicates bi-directionally with the controller circuit 1720 via aconnection 1772 (e.g., electrical connection). The sensing circuitry1740 includes various types of sensing circuitry and sensor(s) includingimage sensor(s) and circuitry 1742, moisture sensor(s) and circuitry1743, temperature sensor(s) and circuitry, humidity sensor(s) andcircuitry, air quality sensor(s) and circuitry, light sensor(s) andcircuitry, motion sensor(s) and circuitry 1744, audio sensor(s) andcircuitry 1745, sensor(s) and circuitry n, etc.

In one embodiment, the sensing circuitry and RF circuitry are integrated(e.g., sensing and communication circuitry 1960, 2060, 2140). In anotherembodiment, the sensing and communication circuitry 1960, 2060, and 2140of FIGS. 19, 20, and 21 are separately located in at least one of asensing circuitry 1740, a controller circuit 1720, and a RF circuitry1770 of FIG. 17. In one example, the sensing circuitry (e.g., 1961,2061, 2141) is located in or integrated with sensing circuitry 1740 andthe communication circuitry 1962, 2062, and 2142 is located in orintegrated with RF circuitry 1770 or controller circuit 1720.

In one embodiment, the components of the vibrational energy harvestingsystem 1900 and 2000 and light energy harvesting system 2100 areintegrated with the sensor node 1700. For example, the vibrationalharvesting circuit 1910, rectifier regulator power conditioner 1920, andcapacitive energy storage 1930 are coupled to the power source selection1940 which is coupled to the primary cell 1950 (e.g., power source 1710)and the sensing and communication circuitry 1960 (e.g., sensingcircuitry 1740 and RF circuitry 1770). In another example, thevibrational harvesting circuit 1910, rectifier regulator powerconditioner 1920, capacitive energy storage 1930, power source selection1940, and primary cell 1950 are integrated with the power source 1710.

In another example, the vibrational harvesting circuit 2010 andrectifier regulator power conditioner battery charger 2020 is coupled tothe rechargeable 2030 cell (e.g., power source 1710) or the vibrationalharvesting circuit 2010 and rectifier regulator power conditionerbattery charger 2020 are integrated with the power source 1710.

In another example, the photovoltaic harvester circuit 2110 and powerconditioner battery charger 2120 is coupled to the rechargeable 2130cell (e.g., power source 1710) or the photovoltaic harvester circuit2110 and power conditioner battery charger 2120 are integrated with thepower source 1710.

The sensor node 1700 can be a wireless device 1700 or the controllercircuit 1720, RF circuitry 1770, sensing circuitry 1740, and antenna(s)1778 in combination may form the wireless device as discussed herein.

In one embodiment, a sensor node (e.g., wireless device) for a wirelessasymmetric network architecture includes at least one sensor, a memoryfor storing instructions, and processing logic coupled to the memory andthe at least one sensor. The processing logic to execute instructionsfor processing data received from the at least one sensor and forprocessing communications for the sensor node. The sensor node alsoincludes a radio frequency (RF) circuitry coupled to the processinglogic. The RF circuitry includes transmitter and receiver functionality(of a transmitter and receiver, respectively, or of a transceiver) totransmit communications to a hub and to receive communications from thehub in the wireless asymmetric network architecture. The processinglogic is configured to execute instructions of a scheduled timing tocause the transmitter functionality to be operable to transmit and tocause the receiver functionality to be operable to receive to reducepower consumption of the sensor node.

In one example, the sensor node is powered by a battery source oranother energy source (not electrical mains source).

In one embodiment, the instructions of the scheduled timing are receivedfrom the hub based on a timing of a communication being transmitted fromthe sensor node to the hub. In another embodiment, the scheduled timingis determined at least partially by the sensor node or another sensornode.

In one embodiment, the transmitter functionality is operable fortransmitting less than 5 percent of a first time period and the receiverfunctionality is operable for receiving less than 5 percent of the firsttime period. In one example, the transmitter functionality is operablefor transmitting less than 1 percent of a first time period and thereceiver functionality is operable for receiving less than 1 percent ofthe first time period.

In one embodiment, the RF circuitry of the sensor node operates at afrequency band greater than 2.4 GigaHertz to minimize a time period fortransmitting in a transmit mode. In another embodiment, the RF circuitryof the sensor node operates at a frequency band greater than 6 GigaHertzto minimize a time period for transmitting in a transmit mode.

In one embodiment, a sensor node for a wireless asymmetric networkarchitecture includes at least one sensor, a memory for storinginstructions, processing logic coupled to the memory and the at leastone sensor. The processing logic executes instructions for processingdata received from the at least one sensor and for processingcommunications for the sensor node. The sensor node also includes radiofrequency (RF) circuitry coupled to the processing logic. The RFcircuitry includes transmitter and receiver functionality (of atransmitter and a receiver, respectively, or of a transceiver) totransmit communications to a hub and to receive communications from thehub in the wireless asymmetric network architecture. The processinglogic is configured to execute instructions to determine a scheduledtiming of operating at least one sensor node during a first time periodthat is close in time with respect to a transmit window of thetransmitter functionality and during a second time period that is closein time with respect to a receive window of the receiver functionalityto reduce power consumption of the sensor node.

In one example, the first time period is approximately the same timeperiod as the transmit window and the second time period isapproximately the same time period as the receive window. In anotherexample, the first time period starts just prior to a time period of thetransmit window and completes just after the transmit window. The firsttime period may be 1-10% longer than the time period of the transmitwindow. The second time period starts just prior to a time period of thereceive window and completes just after the receive window. The secondtime period may be 1-10% longer than the time period of the receivewindow.

In one example, the sensor node is powered by a battery source oranother energy source (not mains electrical source).

In one embodiment, the sensor node to operate with a battery source andenergy from energy harvesting is stored either directly in the batteryif it is rechargeable, or in a capacitor coupled to the sensor node orintegrated with the sensor node. The energy from energy harvesting isused to supplement energy drawn from the battery source duringoperation.

In one embodiment, the sensor node operates at a first power consumptionlevel for the first and second time periods. The sensor node can operateat a second power consumption level when outside of the first and secondtime periods. In this example, the first power consumption level hasmore power consumption than the second power consumption level.

In one embodiment, a sensor node for a wireless asymmetric networkarchitecture includes at least one sensor, a memory for storinginstructions, and processing logic coupled to the memory and the atleast one sensor. The processing logic to execute instructions forprocessing data (e.g., image data, motion data, moisture data,temperature data, etc.) received from the at least one sensor and forprocessing communications received or to be transmitted for the sensornode. The sensor node also includes radio frequency (RF) circuitrycoupled to the processing logic. The RF circuitry includes transmitterand receiver functionality to transmit communications to a hub and toreceive communications from the hub in the wireless asymmetric networkarchitecture. The processing logic is configured to process acommunication received from a hub that indicates a transmit window forthe transmitter functionality and a receive window for the receiverfunctionality of the sensor node to provide anti-collision features toavoid collisions of communications in the wireless asymmetric networkarchitecture.

In one example, the sensor node is powered by a battery source oranother energy source.

In one embodiment, the processing logic is configured to executeinstructions to process the communication received from the hub thatindicates a shift of a next transmit window and next receive window forthe sensor node. The processing logic can also be configured to executeinstructions to generate at least one random number and to shift atleast one of a future transmit window and/or a future receive window forthe sensor node based on the at least one random number when the hubdetermines that collision has occurred for communications received fromthe sensor node and another node.

In one embodiment, a machine-accessible non-transitory medium (e.g.,memory) contains executable computer program instructions which whenexecuted by a data processing system cause the system to perform any ofthe methods discussed herein. While the machine-accessiblenon-transitory medium is shown in an exemplary embodiment to be a singlemedium, the term “machine-accessible non-transitory medium” should betaken to include a single medium or multiple media (e.g., a centralizedor distributed database, and/or associated caches and servers) thatstore the one or more sets of instructions. The term “machine-accessiblenon-transitory medium” shall also be taken to include any medium that iscapable of storing, encoding or carrying a set of instructions forexecution by the machine and that cause the machine to perform any oneor more of the methodologies of the present invention. The term“machine-accessible non-transitory medium” shall accordingly be taken toinclude, but not be limited to, solid-state memories, optical andmagnetic media, and carrier wave signals.

An apparatus (e.g., hub 610, hub 720, hub 782, hub n, hub 820, hub 964,hub 984, hub 1882, etc.) for providing a wireless asymmetric networkarchitecture with power management features includes a memory (e.g.,memory 842, memory 961, memory 986, memory 1886) for storinginstructions, processing logic (e.g., one or more processing units,processing logic 844, processing logic 963, processing logic 988,processing logic 1888) to execute instructions to establish and controlcommunications in the wireless asymmetric network architecture, andradio frequency (RF) circuitry (e.g., RF circuitry 850, RF circuitry970, RF circuitry 992, RF circuitry 1890)

In one embodiment, an apparatus (e.g., hub 610, hub 720, hub 782, hub n,hub 820, hub 964, hub 984, hub 1882, etc.) is a wireless control deviceor includes a wireless control device for providing a wirelessasymmetric network architecture. The apparatus includes memory (e.g.,memory 842, memory 961, memory 986, memory 1886) for storinginstructions, processing logic (e.g., one or more processing units,processing logic 844, processing logic 963, processing logic 988,processing logic 1888) to execute instructions to establish and controlcommunications in the wireless asymmetric network architecture, and RFcircuitry (e.g., transceiver, RF circuitry 850, RF circuitry 970, RFcircuitry 992, RF circuitry 1890) to transmit and receive communicationsin the wireless asymmetric network architecture. The RF circuitrytransmits communications to a plurality of nodes each having a wirelessdevice with a transmitter and a receiver to enable bi-directionalcommunications with the RF circuitry in the wireless asymmetric networkarchitecture. The processing logic is configured to execute instructionsto determine a scheduled timing of causing the transmitter to beoperable to transmit and causing the receiver to be operable to receivefor each wireless device to reduce power consumption of the wirelessdevices of the plurality of nodes.

In one example, the apparatus is powered by a mains electrical sourceand the plurality of nodes are each powered by a battery source oranother energy source (not mains electrical source) to form the wirelessasymmetric network.

The scheduled timing of powering the transmitter and powering thereceiver for each wireless device is determined based on a timing ofcommunications between the transceiver of the apparatus and eachwireless device of the nodes. In one example, the scheduled timing ofcausing the receiver to be operable to receive for at least one wirelessdevice of a terminal node of the nodes (or other nodes) is determinedbased on a timing of a communication being transmitted from the at leastone wireless device to the RF circuitry of the apparatus.

In another example, the apparatus is aware of when the receivers of thewireless devices of the nodes are active (e.g., in receive mode) basedon the timing of the transmitted communications from the wirelessdevices of the nodes to the apparatus. For example, if a transmitter ofa wireless device transmits a communication to the apparatus, then theapparatus will know that a receiver of this wireless device, which canbe a terminal node or other node, will be active for a certain timeperiod after the communication is transmitted to the apparatus.

In one embodiment, the transmitter for each wireless device is operablefor transmitting less than a certain percentage (e.g., 5 percent, 1percent) of a time period and the receiver for each wireless device isoperable for receiving less than a certain percentage (e.g., 5 percent,1 percent) of the time period.

In one example, the wireless asymmetric network architecture includes atleast one of a wireless tree asymmetric network architecture or awireless tree and mesh asymmetric network architecture.

FIG. 18 illustrates a block diagram of a system 1800 having a hub inaccordance with one embodiment. The system 1800 includes or isintegrated with a hub 1882 or central hub of a wireless asymmetricnetwork architecture. The system 1800 (e.g., computing device, smart TV,smart appliance, communication system, etc.) may communicate with anytype of wireless device (e.g., cellular phone, wireless phone, tablet,computing device, smart TV, smart appliance, etc.) for sending andreceiving wireless communications. The system 1800 includes a processingsystem 1810 that includes a controller 1820 and processing units 1814.The processing system 1810 communicates with the hub 1882, anInput/Output (I/O) unit 1830, radio frequency (RF) circuitry 1870, audiocircuitry 1860, an optics device 1880 for capturing one or more imagesor video, an optional motion unit 1844 (e.g, an accelerometer,gyroscope, etc.) for determining motion data (e.g., in three dimensions)for the system 1800, a power management system 1840, andmachine-accessible non-transitory medium 1850 via one or morebi-directional communication links or signal lines 1898, 1818, 1815,1816, 1817, 1813, 1819, 1811, respectively.

The hub 1882 includes a power supply 1891 that provides power (e.g., DCpower supply) to a controller circuit 1884 via a connection 1885 (e.g.,communication link, signal line, electrical connection, etc.) andprovides power to RF circuitry 1890 via a connection 1887 (e.g.,communication link, signal line, electrical connection, etc.). Thecontroller circuit 1884 includes memory 1886 or is coupled to memorythat stores instructions which are executed by processing logic 1888(e.g., one or more processing units) of the controller circuit 1884 forcontrolling operations of the hub for forming and monitoring thewireless asymmetrical network as discussed herein. The RF circuitry 1890may include a transceiver or separate transmitter (TX) 1892 and receiver(RX) 1894 functionality for sending and receiving bi-directionalcommunications via antenna(s) 1896 with the wireless sensor nodes orother hubs. The RF circuitry 1890 communicates bi-directionally with thecontroller circuit 1884 via a connection 1889 (e.g., communication link,signal line, electrical connection, etc.). The hub 1882 can be awireless control device 1884 or the controller circuit 1884, RFcircuitry 1890, and antenna(s) 1896 in combination may form the wirelesscontrol device as discussed herein.

RF circuitry 1870 and antenna(s) 1871 of the system or RF circuitry 1890and antenna(s) 1896 of the hub 1882 are used to send and receiveinformation over a wireless link or network to one or more otherwireless devices of the hubs or sensors nodes discussed herein. Audiocircuitry 1860 is coupled to audio speaker 1862 and microphone 1064 andincludes known circuitry for processing voice signals. One or moreprocessing units 1814 communicate with one or more machine-accessiblenon-transitory mediums 1850 (e.g., computer-readable medium) viacontroller 1820. Medium 1850 can be any device or medium (e.g., storagedevice, storage medium) that can store code and/or data for use by oneor more processing units 1814. Medium 1850 can include a memoryhierarchy, including but not limited to cache, main memory and secondarymemory.

The medium 1850 or memory 1886 stores one or more sets of instructions(or software) embodying any one or more of the methodologies orfunctions described herein. The software may include an operating system1852, network services software 1856 for establishing, monitoring, andcontrolling wireless asymmetric network architectures, communicationsmodule 1854, and applications 1858 (e.g., home or building securityapplications, home or building integrity applications, developerapplications, etc.). The software may also reside, completely or atleast partially, within the medium 1850, memory 1886, processing logic1888, or within the processing units 1814 during execution thereof bythe device 1800. The components shown in FIG. 18 may be implemented inhardware, software, firmware or any combination thereof, including oneor more signal processing and/or application specific integratedcircuits.

Communication module 1854 enables communication with other devices. TheI/O unit 1830 communicates with different types of input/output (I/O)devices 1834 (e.g., a display, a liquid crystal display (LCD), a plasmadisplay, a cathode ray tube (CRT), touch display device, or touch screenfor receiving user input and displaying output, an optional alphanumericinput device).

In the foregoing specification, the invention has been described withreference to specific exemplary embodiments thereof. It will, however,be evident that various modifications and changes may be made theretowithout departing from the broader spirit and scope of the invention.The specification and drawings are, accordingly, to be regarded in anillustrative rather than a restrictive sense.

What is claimed is:
 1. A system for providing a wireless asymmetricnetwork architecture, comprising: a first hub having a wireless controldevice that is configured to control communications and powerconsumption in the wireless asymmetric network architecture; and a firstplurality of sensor nodes each having at least one sensor and a wirelessdevice with a transmitter and a receiver to enable bi-directionalcommunications with the wireless control device of the first hub in thewireless asymmetric network architecture, wherein the wireless controldevice is configured to receive a communication from a wireless deviceof a sensor node or from a second hub and to determine a scheduledtiming of operating each sensor node at a low-energy non-communicativestate for a first time period and at a communicative state for a secondtime period based on a timing of receiving the communication to reducepower consumption of the wireless devices of the first plurality ofsensor nodes, wherein the first hub is powered by a mains electricalsource and the first plurality of sensor nodes are each powered by abattery source to form the wireless asymmetric network architecture. 2.The system of claim 1, wherein the first hub to transmit periodiccommunications to the first plurality of sensor nodes to reduce powerconsumption of the wireless devices of the first plurality of sensornodes.
 3. The system of claim 1, wherein the wireless control device isconfigured to determine a scheduled timing of a transmit window of thetransmitter and a receive window of the receiver for each wirelessdevice based on a timing of receiving a communication from each wirelessdevice of the first plurality of sensor nodes.
 4. The system of claim 1,wherein at least one sensor node transitions from the low-energynon-communicative state to the communicative state upon receiving acommunication from the hub or a sensor node.
 5. The system of claim 1,wherein at least one sensor node transitions from the low-energynon-communicative state to the communicative state upon receiving acommunication from the hub or a sensor node.
 6. The system of claim 5,wherein the at least one sensor node transitions from the communicativestate for localization to the low-energy non-communicative state uponcompleting localization.
 7. The system of claim 1, wherein at least onesensor node operates at a first clock frequency for the low-energynon-communicative state and a second clock frequency for thecommunicative state.
 8. The system of claim 1, wherein at least onesensor node operates at a frequency of approximately 2.4 GHz or 5 GHzfor the communicative state and a frequency of approximately 900 MHz or2.4 GHz for the low-energy non-communicative state.
 9. The system ofclaim 1, wherein at least one sensor node sends a communication to thefirst hub to initiate localization.
 10. The system of claim 8, furthercomprising: a second plurality of sensor nodes each having at least onesensor and a wireless device with a transmitter and a receiver to enablebi-directional communications with a wireless control device of thesecond hub in the wireless asymmetric network architecture, wherein thewireless control device is configured to determine a scheduled timing ofoperating each sensor node during a time period that is close in timewith respect to a transmit window of the transmitter and during a timeperiod that is close in time with respect to a receive window of thereceiver for each wireless device to reduce power consumption of thewireless devices of the second plurality of sensor nodes.
 11. The systemof claim 1, wherein the wireless asymmetric network architecturecomprises a wireless tree asymmetric network architecture or a wirelesstree and mesh asymmetric network architecture.
 12. The system of claim1, wherein each sensor node operates at a first power consumption levelfor the low-energy non-communicative state.
 13. The system of claim 11,wherein each sensor node operates at a second power consumption levelfor the communicative state, wherein the second power consumption levelhas more power consumption than the first power consumption level. 14.An apparatus for providing a wireless asymmetric network architecture,comprising: a memory for storing instructions; one or more processingunits to execute instructions to establish and control communications inthe wireless asymmetric network architecture; and radio frequency (RF)circuitry to transmit and receive communications in the wirelessasymmetric network architecture, the RF circuitry to transmitcommunications to a plurality of sensor nodes each having at least onesensor and a wireless device with a transmitter and a receiver to enablebi-directional communications with the RF circuitry of the apparatus inthe wireless asymmetric network architecture, wherein the one or moreprocessing units are configured to receive a communication from awireless device of a sensor node or from another apparatus and todetermine a scheduled timing of operating each sensor node at alow-energy non-communicative state for a first time period and at acommunicative state for a second time period based on a timing ofreceiving the communication to reduce power consumption of the wirelessdevices of the plurality of sensor nodes, wherein the apparatus ispowered by a mains electrical source and the plurality of sensor nodesare each powered by a battery source to form the wireless asymmetricnetwork architecture.
 15. The apparatus of claim 14, wherein theapparatus to transmit periodic communications to the plurality of sensornodes to reduce power consumption of the wireless devices of theplurality of sensor nodes.
 16. The apparatus of claim 14, wherein atleast one sensor node transitions from the low-energy non-communicativestate to the communicative state upon receiving a communication from theapparatus or a sensor node.
 17. A sensor node for a wireless asymmetricnetwork architecture, comprising: at least one sensor; a memory forstoring instructions; processing logic coupled to the memory and the atleast one sensor, the processing logic to execute instructions forprocessing data received from the at least one sensor and for processingcommunications for the sensor node; and radio frequency (RF) circuitrycoupled to the processing logic, the RF circuitry includes transmitterand receiver functionality to transmit communications to a hub and toreceive communications from the hub in the wireless asymmetric networkarchitecture, wherein the processing logic is configured to executeinstructions to receive a first communication from the hub or totransmit a second communication to the hub and to determine a scheduledtiming of operating the sensor node at a low-energy non-communicativestate for a first time period and at a communicative state for a secondtime period based on a timing of receiving the first communication ortransmitting the second communication to reduce power consumption of thesensor node, wherein the hub is powered by a mains electrical source andthe sensor node is powered by a battery source to form the wirelessasymmetric network architecture.
 18. The sensor node of claim 17,wherein the sensor node to receive periodic communications from the hubto reduce power consumption.
 19. The sensor node of claim 17, whereinthe processing logic is configured to provide instructions fordetermining a scheduled timing of a transmit window of the transmitterand a receive window of the receiver for the sensor node based on atiming of receiving the first communication from the hub or transmittingthe second communication to the hub.
 20. The sensor node of claim 17,wherein the sensor node transitions from the low-energynon-communicative state to the communicative state upon receiving acommunication.
 21. The sensor node of claim 17, wherein the sensor nodeoperates at a first clock frequency for the low-energy communicativestate and a second clock frequency for the communicative state.
 22. Thesensor node of claim 17, wherein the sensor node operates at a frequencyof approximately 2.4 GHz or 5 GHz for the communicative state and afrequency of approximately 900 MHz or 2.4 GHz for the low-energynon-communicative state.
 23. The sensor node of claim 17, wherein thesensor node operates at a frequency of ultra-wide-band (UWB) for thecommunicative state.